In semiconductor technologies, image sensors are used for sensing a volume of exposed light projected towards a semiconductor substrate. Complementary metal-oxide-semiconductor (CMOS) image sensors (CIS) and charge-coupled device (CCD) sensors are widely used in various applications such as digital still camera applications. These devices utilize an array of pixels or image sensor elements, including photodiodes and transistors, to collect photo energy to convert images into electrical signals.
However, image sensor devices suffer from cross-talk. That is, light targeted for one image sensor element (and the electrical signal generated thereby) may spread to neighboring image sensor elements, which causes cross-talk. Cross-talk will degrade spatial resolution, reduce overall optical sensitivity, and result in poor color separation.
Therefore, what is needed is a simple and cost-effective device and method for reducing cross-talk in image sensors.